Levitt, M.H., Symmetry constraints on spin dynamics: Application to hyperpolarized NMR. J Magn Reson, 2016. 262: p. 91-9.
http://www.ncbi.nlm.nih.gov/pubmed/26462592
Spin dynamical evolution is constrained by the symmetries of the spin Hamiltonians that generate the quantum dynamics. The consequences of symmetry-induced constraints are examined for some common hyperpolarized NMR experiments, including the excitation of singlet order in spin-pair systems, and the transfer of parahydrogen-induced hyperpolarized singlet order to magnetization in systems displaying chemical and magnetic equivalence.